Job Control Language (JCL) is a script language developed by International Business Machines Corporation to control execution of programs and batch systems run on the IBM MVS mainframe system. JCL includes scripts that tell a job controller what to do when the job controller attempts to run a job. JCL programs include a series of instructions that are typically placed at the beginning of a job to specify how the mainframe system should process the job. The instructions may specify computer resource allocations, the identity of physical and logical resources to which output data is to be written and the identity of physical and logic resources from which input data is to be received. The instructions are organized sequentially in the order in which they are to be executed.
Each JCL job controls a production job stream that consists of a series of software programs that perform some business process. Typically, production control personnel monitor the progress of a job stream to ensure the job stream is completed as intended. The production control personnel take action when a JCL job step exhibits an abnormal condition. The documentation for the job identifies what actions are to be taken in response to such an abnormal condition. For example, the actions may include restarting a job step or paging on-call support personnel.
A JCL job is typically kept in a separate partitioned data set relative to the documentation. Oftentimes, the documentation data set has the same name as the JCL job data set but is placed in a separate library. Hence, if the production control personnel need to reference documentation for a JCL job, they may search for the data set with the same name as the JCL job that is in the documentation library.
Unfortunately, JCL job documentation is often inconsistent, inaccurate or absent. In many instances, the JCL job documentation is kept in a freeform style of textual notes written by software developers. The difficulty with this lack of consistency in the documentation is that it makes it difficult for production control personnel to accurately respond to abnormal conditions. As a result, delays in job processing may occur, resulting in a loss of time and income.